Plastic Used on Makina 67 / 670 (and other cameras of the 1980s)

jbf · Dec 30, 2022

Does anyone know what type of plastic is used for the body shell of the Plaubel Makina 67 / 670 / W67 cameras made by Mamiya in 1980s?

I know ABS is used widely for consumer electronics due to its strength and was likely popular during this time period as well.

I've got a crack on my Makina 67 right at the corner near the shutter button / thumb wheel and winder. If it is ABS plastic, then I can fix it using an ABS / Acetone mixture with careful taping and application.

Anyone have thoughts or insight into plastic type?

Nitroplait · Dec 30, 2022

I don't have the answer for your camera, but the other commonly mentioned plastic used for cameras is polycarbonate, but I think it was mostly used for chromed top plates and not body shells. The fact that you see a crack makes me suspect it is not polycarbonate.
Good luck finding the answer.

gone · Dec 30, 2022

I had a Mamiya 6 that had a crack in exactly the same place. Epoxy will usually work on just about anything.

Dan Daniel · Dec 30, 2022

You do a test with acetone or an appropriate solvent to see if the material reacts. If you can get inside and find a place to put a drop and see if it melts or simply evaporates with no effect, you'll get an answer (you'll need to lightly poke the plastic).

Weld-on #4 is what I used to use for similar operations. It evaporates a bit slower than acetone. They don't mention ABS but it does work for exactly what you want to do.

Weld-On 4 – Weld-On Sign & Display Assembly Adhesives

assemblyadhesives.com

jbf · Jan 3, 2023

This is very helpful thanks everyone. Dan I'll try the acetone test. Only worry about epoxy is how strong the repair will be since it wont likely penetrate the crack itself.
I've heard sometimes putting a thin piece of metal and epoxying that over the crack can give good reinforcement as well.

I may just try the ABS slurry as used in 3D printing so that itll seep into the crack.

Dan Daniel · Jan 3, 2023

Another approach is to drill or slice and embed a metal pin or a plate. If you can't get a solvent action, the reinforcement can help the epoxy. Even better if you can heat-sink the metal into the plastic parts.

Or create a notch on both pieces and screw/glue a plate across the seam and reshape to fit.

jbf · Jan 3, 2023

Dan Daniel said:
Another approach is to drill or slice and embed a metal pin or a plate. If you can't get a solvent action, the reinforcement can help the epoxy. Even better if you can heat-sink the metal into the plastic parts.

Or create a notch on both pieces and screw/glue a plate across the seam and reshape to fit.

This sounds similar to fitting a bow-tie in woodworking to stop a wood crack from spreading. Very cool. Plastic is pretty thin on the shell of these cameras so might be hard to embed into it without going al the way through the shell. Could be an interesting battle scar or akin to Kintsugi ceramic repair.

Dan Daniel · Jan 3, 2023

jbf said:
This sounds similar to fitting a bow-tie in woodworking to stop a wood crack from spreading. Very cool. Plastic is pretty thin on the shell of these cameras so might be hard to embed into it without going al the way through the shell. Could be an interesting battle scar or akin to Kintsugi ceramic repair.

If you can find a little piece of rosewood...

Plastic Used on Makina 67 / 670 (and other cameras of the 1980s)

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